CopilotKit has released AG-UI 1.0, the first stable version of the Agent-User Interaction Protocol, an open standard that defines a shared event stream between agent backends and user-facing applications. The release pairs a full specification with a JSON Schema that fixes the exact fields every event carries, and the TypeScript, Python and .NET SDKs are now generated from that schema instead of being maintained by hand. AG-UI is adopted by Google, Microsoft, Amazon and Oracle and supported by frameworks including LangChain, Mastra and Anthropic’s Claude Managed Agents. Version 1.0 adds subagent support, custom metadata, multimodal tool results, human-in-the-loop interrupts and token usage reporting, and it is backwards compatible, so 0.x agents work with 1.0 clients and the reverse.

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Introducing AG-UI 1.0